1. Field of the Invention
The invention relates to an automatic flushing device, more particularly to a water and energy efficient automatic flushing device.
2. Description of the Related Art
Automatic flushing devices for controlling the flow of water to a plumbing fixture, such as a toilet bowl or urinal, are known in the art. One such type provides a first flushing action upon detection of a person using the plumbing fixture, thereby keeping the plumbing fixture clean and moist, and a second flushing action to wash away human waste. The disadvantages of conventional automatic flushing devices are as follows:
1. False operation of the flushing device often occurs. Electromagnetic interference (EMI), radio frequency interference (RFI) or even reflected light can cause untimely activation of the conventional flushing devices. This results in higher and less efficient water consumption.
2. Electrical consumption of the conventional flushing devices is relatively high since signal transmission continuously occurs.
3. When the elapsed time starting from the departure of a preceding user from the plumbing fixture up to the detection of a succeeding user using the plumbing fixture is relatively short, the first flushing action for the succeeding user is unnecessary since the second flushing action of the preceding user is sufficient to keep the plumbing fixture moist and clean. Unnecessary flushing of the plumbing fixture results in higher and less efficient water consumption.